Thin fan structure

ABSTRACT

A thin fan structure includes a case, a fan impeller, a circuit board, a silicon steel sheet and a winding assembly. The case has a receiving space and a bearing cup protruding into the receiving space. The bearing cup is formed with a bearing hole. The fan impeller has a hub section, multiple blades and a shaft extending from a center of the hub section. A magnetic member is annularly disposed on inner circumference of the hub section. The circuit board is disposed in the receiving space. The silicon steel sheet disposed on the circuit board has a base section and multiple first magnetic conductive sections, which together define a receiving space. The winding assembly is fixedly disposed in the receiving space. The winding assembly has a bottom section attached to the base section and a side section attached to the first magnetic conductive sections.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a thin fan structure, and more particularly to a thin fan structure, which has a greatly minified volume and greatly thinned thickness.

2. Description of the Related Art

Nowadays, there is a trend to develop high-function electronic products and miniaturize the high-function electronic products. Along with the development of these electronic products, heat dissipation techniques have been more and more improved to enhance the heat dissipation performance. The conventional cooling fan has the advantages of low cost and mature technique. Therefore, various cooling fans are popularly used as heat dissipation devices.

Please refer to FIG. 1. The conventional cooling fan 1 includes a stator assembly 10 and a rotor 11 for operating the fan under change of polarity. The stator assembly 10 is composed of multiple stacked silicon steel sheets 101 and multiple windings 102 wound on the silicon steel sheets 101. The silicon steel sheets 101 are axially stacked to form the stator assembly 10, whereby the conventional cooling fan 1 can be provide a good heat dissipation effect. However, currently, there is a trend to develop lighter, thinner and smaller electronic products. In the case that the volume of the cooling fan 1 is reduced and the axial thickness of the cooling fan 1 is thinned, the heat dissipation efficiency will be lowered. Moreover, it is difficult to manufacture the thinned cooling fan.

Please now refer to FIG. 2, which shows a conventional thin fan structure 2. The conventional thin fan structure 2 includes a base seat 20, a fan impeller 21, a plate-shaped magnet 22, a shaft rod 23 and a bearing 24. The base seat 20 is formed with a bearing hole 201. A winding assembly 202 is disposed on the base seat 20. The fan impeller 21 has multiple blades 211. The plate-shaped magnet 22 is connected under the fan impeller 21. The bearing 24 is received in the bearing hole 201. One end of the shaft rod 23 is inserted in the shaft hole 241 of the bearing 24. The other end of the shaft rod 23 is connected with the fan impeller 21. The thin fan structure 2 is installable on various electronic devices or electronic instruments to provide a predetermined heat dissipation effect.

However, the plate-shaped magnet 22 and the winding assembly 202 of the conventional thin fan 2 together define a certain axial height. Therefore, it is hard to further reduce the total axial height of the thin fan 2. As a result, the possibility of further miniaturization of the fan is lowered. In addition, the plate-shaped magnet 22 and the winding assembly 202 are axially arranged in parallel to each other. Therefore, in operation, the fan will vibrate to a greater extent to make noise.

According to the above, the conventional thin fan has the following shortcomings:

1. The fan cannot be further thinned.

2. The heat dissipation efficiency of the fan is lowered.

3. The fan will make noise.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide a thin fan structure, which has a greatly minified volume and greatly thinned thickness.

It is a further object of the present invention to provide the above thin fan structure, which is manufactured at a much lower cost.

It is still a further object of the present invention to provide the above thin fan structure, which has higher heat dissipation efficiency.

To achieve the above and other objects, the thin fan structure of the present invention includes a case, a fan impeller, a circuit board, a silicon steel sheet and a winding assembly. The case has a receiving space and a bearing cup protruding from a center of the case into the receiving space. The bearing cup is formed with a bearing hole. A bearing with a shaft hole is disposed in the bearing hole. The fan impeller has a hub section and multiple blades outward extending from a circumference of the hub section. A shaft axially extends from a center of the hub section. The shaft is inserted in the shaft hole. A magnetic member is annularly disposed on inner circumference of the hub section. The circuit board is disposed in the receiving space and fitted around the bearing cup. The silicon steel sheet is disposed on the circuit board. The silicon steel sheet has a base section and multiple first magnetic conductive sections upward protruding from a circumference of the base section. The base section and the first magnetic conductive sections together define a receiving space. The winding assembly is fixedly disposed in the receiving space. The winding assembly has a bottom section and a side section. The bottom section is attached to the base section. The side section is correspondingly attached to the first magnetic conductive sections.

According to the above structural design, the winding assembly is securely disposed in the receiving space of the silicon steel sheet and the magnetic member is annularly disposed on the inner circumference of the hub section. In this case, the volume of the fan is greatly reduced and the thickness of the fan is greatly thinned. In comparison with the conventional cooling fan, the present invention is advantageous in that the heat dissipation efficiency of the thinned fan will not be deteriorated. In addition, the manufacturing process of the thin fan structure of the present invention is simplified so that the working time is shortened and the manufacturing cost is greatly lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein:

FIG. 1 is a perspective exploded view of a conventional cooling fan;

FIG. 2 is a perspective exploded view of a conventional thin fan structure;

FIG. 3 is a perspective exploded view of a first embodiment of the thin fan structure of the present invention;

FIG. 4 is a perspective assembled view of the first embodiment of the thin fan structure of the present invention;

FIG. 5 is a sectional view of the first embodiment of the thin fan structure of the present invention;

FIG. 6 is a perspective view of the silicon steel sheet of a second embodiment of the thin fan structure of the present invention;

FIG. 7A is a perspective view of the silicon steel sheet of a third embodiment of the thin fan structure of the present invention;

FIG. 7B is a perspective view of the silicon steel sheet of a fourth embodiment of the thin fan structure of the present invention; and

FIG. 8 is a perspective view of the silicon steel sheet of a fifth embodiment of the thin fan structure of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 3, 4 and 5. FIG. 3 is a perspective exploded view of a first embodiment of the thin fan structure of the present invention. FIG. 4 is a perspective assembled view of the first embodiment of the thin fan structure of the present invention. FIG. 5 is a sectional view of the first embodiment of the thin fan structure of the present invention. According to the first embodiment, the thin fan structure 3 of the present invention includes a case 31, a fan impeller 32, a circuit board 34, a silicon steel sheet 35 and a winding assembly 36. The case 31 has a receiving space 313 and a bearing cup 311 protruding from a center of the case 31 into the receiving space 313. The bearing cup 311 is formed with a bearing hole 312. A bearing 37 with a shaft hole 371 is received in the bearing hole 312.

The fan impeller 32 has a hub section 321 and multiple blades 322 outward extending from the circumference of the hub section 321. A shaft 323 axially extends from the center of the hub section 321. The shaft 323 is rotatably disposed in the shaft hole 371. A magnetic member 33 is annularly disposed on inner circumference of the hub section 321.

The circuit board 34 is disposed in the receiving space 313 and fitted around the bearing cup 311.

The silicon steel sheet 35 is disposed on the circuit board 34. The silicon steel sheet 35 has a base section 351 and multiple first magnetic conductive sections 352 upward protruding from a circumference of the base section 351. The base section 351 and the first magnetic conductive sections 352 are integrally formed to together define a receiving space 353. The first magnetic conductive sections 352 are discontinuously arranged on the circumference of the base section 351 at intervals.

The winding assembly 36 is fixedly disposed in the receiving space 353. The winding assembly 36 is a self-adhesive winding assembly having a bottom section 361 and a side section 362. The bottom section 361 is attached to the base section 351. The side section 362 is correspondingly attached to the first magnetic conductive sections 352. In this embodiment, the winding assembly 36 is, but not limited to, fixed in the receiving space 353 of the silicon steel sheet 35 by means of press fit or adhesion. Alternatively, the winding assembly 36 can be disposed in the receiving space 353 of the silicon steel sheet 35 by any other means that can secure the winding assembly 36 in the receiving space 353.

According to the above structural design, the winding assembly 36 is securely disposed in the receiving space 353 of the silicon steel sheet 35 and the magnetic member 33 is annularly disposed on the inner circumference of the hub section 321. In this case, the axial height of the fan is greatly reduced to minify the volume of the fan and thin the fan. In comparison with the conventional cooling fan, the present invention is advantageous in that the heat dissipation efficiency of the thinned fan will not be deteriorated. That is, even with the axial height of the fan reduced, the thinned fan still can provide high heat dissipation efficiency.

In addition, the manufacturing process of the thin fan structure 3 of the present invention is simplified so that the working time is shortened and the manufacturing cost is lowered. Also, the magnetic member 33 is disposed on the inner circumference of the hub section 321 so that the thin fan structure of the present invention has a smaller volume and thinner thickness than the conventional fan structure. Furthermore, the axial vibration of the present invention is obviously smaller than that of the conventional cooling fan so that the problems of vibration and noise made in operation of the fan can be overcome.

Please now refer to FIG. 6, which is a perspective view of the silicon steel sheet of a second embodiment of the thin fan structure of the present invention. The second embodiment is partially identical to the first embodiment in component and connection relationship between the components and thus will not be repeatedly described hereinafter. The second embodiment is mainly different from the first embodiment in that four first magnetic conductive sections 352 protrude from the circumference of the base section 351. In practice, the number of the first magnetic conductive sections 352 is adjustable according to the requirement of a user.

Please now refer to FIGS. 7A and 7B. FIG. 7A is a perspective view of the silicon steel sheet of a third embodiment of the thin fan structure of the present invention. FIG. 7B is a perspective view of the silicon steel sheet of a fourth embodiment of the thin fan structure of the present invention. The third and fourth embodiments are partially identical to the first embodiment in component and connection relationship between the components and thus will not be repeatedly described hereinafter. The third and fourth embodiments are mainly different from the first embodiment in that multiple second magnetic conductive sections 354 protrude from the circumference of the base section 351 in a direction reverse to that of the first magnetic conductive sections 352. The first and second magnetic conductive sections 352, 354 are reversely arranged in alignment with each other (as shown in FIG. 7A) or reversely alternately arranged (as shown in FIG. 7B). The first and second magnetic conductive sections 352, 354 are integrally formed. The second magnetic conductive sections 354 are such arranged as to provide a space for avoiding the electronic components on the circuit board 34.

Please now refer to FIG. 8, which is a perspective view of the silicon steel sheet of a fifth embodiment of the thin fan structure of the present invention. The fifth embodiment is partially identical to the first embodiment in component and connection relationship between the components and thus will not be repeatedly described hereinafter. The fifth embodiment is mainly different from the first embodiment in that the base section 351 is further formed with multiple perforations 355. Each first magnetic conductive section 352 has a magnetic conductive portion 3521 protruding from one side of the first magnetic conductive section 352. The perforations 355 are for easy location of the silicon steel sheet 35. Also, by means of the perforations 355, the silicon steel sheet 35 can be more easily assembled on the thin fan structure 3.

In conclusion, in comparison with the conventional cooling fan, the present invention has the following advantages:

1. The volume is greatly minified to thin the fan.

2. The working time is greatly shortened and the manufacturing cost is greatly lowered.

3. The heat dissipation efficiency is increased.

4. The vibration and noise made by the fan are reduced.

The present invention has been described with the above embodiments thereof and it is understood that many changes and modifications in the above embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

What is claimed is:
 1. A thin fan structure comprising: a case having a receiving space and a bearing cup protruding from a center of the case into the receiving space, the bearing cup being formed with a bearing hole; a fan impeller having a hub section and multiple blades outward extending from a circumference of the hub section, a shaft axially extending from a center of the hub section, the shaft being rotatably disposed in the bearing hole, a magnetic member being annularly disposed on inner circumference of the hub section; a circuit board disposed in the receiving space and fitted around the bearing cup; a silicon steel sheet disposed on the circuit board, the silicon steel sheet having a base section and multiple first magnetic conductive sections upward protruding from a circumference of the base section, the base section and the first magnetic conductive sections together defining a receiving space; and a winding assembly fixedly disposed in the receiving space, the winding assembly having a bottom section and a side section, the bottom section being attached to the base section, the side section being correspondingly attached to the first magnetic conductive sections.
 2. The thin fan structure as claimed in claim 1, wherein a bearing with a shaft hole is received in the bearing hole, the shaft being inserted in the shaft hole.
 3. The thin fan structure as claimed in claim 1, wherein the first magnetic conductive sections are discontinuously arranged on the circumference of the base section at intervals.
 4. The thin fan structure as claimed in claim 1, wherein the winding assembly is connected with the silicon steel sheet by means of press fit or adhesion.
 5. The thin fan structure as claimed in claim 1, wherein the winding assembly is a self-adhesive winding assembly.
 6. The thin fan structure as claimed in claim 1, wherein multiple second magnetic conductive sections protrude from the circumference of the base section in a direction reverse to that of the first magnetic conductive sections.
 7. The thin fan structure as claimed in claim 6, wherein the first and second magnetic conductive sections are reversely arranged in alignment with each other.
 8. The thin fan structure as claimed in claim 6, wherein the first and second magnetic conductive sections are reversely alternately arranged.
 9. The thin fan structure as claimed in claim 6, wherein the first and second magnetic conductive sections are integrally formed.
 10. The thin fan structure as claimed in claim 1, wherein the base section is formed with multiple perforations.
 11. The thin fan structure as claimed in claim 1, wherein each first magnetic conductive section has a magnetic conductive portion protruding from one side of the first magnetic conductive section. 